CMOS主動電感於單磊晶微波積體電路極小化之應用與實現
Application and implementation of monolithic microwave integated circuits with CMOS active inductors
Date Issued
2005
Date
2005
Author(s)
Liao, Yu-Te
DOI
en-US
Abstract
With the increasing demands on wireless communication devices, the issues of the low-cost and high-level integration are the trend for the implementation of RF front-end system. With recent advances in deep submicron fabrication process, CMOS technology is showing the potential to meet these requirements. Due to the use of transmission lines, it is not practical to integrate the microwave hybrids and phase shifters monolithically. Therefore, the lumped-element replacement has been proposed to reduce the chip size. Though the minimized chip size can be achieved, they still suffer from the loss due to low Q-factor passive components in standard CMOS process. In this thesis, active inductors are employed to substitute the spiral inductors, providing high Q-factors, tunable inductance and miniaturized chip area. Based on this concept, the analog phase shifter, Wilkinson power divider and quadrature hybrid are implemented in the standard 0.18-um CMOS process for monolithic microwave integrated circuit (MMIC) applications.
By employing active inductors in the synthetic transmission line architecture, the phase shifter exhibits a wide phase control range, low insertion loss and miniaturized chip area. Characterized by the S-parameter measurement, the fabricated circuit demonstrates an insertion loss less than 1.1 dB within the 360 phase shift while maintaining a return loss better than 10 dB from 3.5 to 4.5 GHz. Due to the absence of distributed elements and spiral inductors, the area of the phase shifter core is 400x200 um2. The power divider is designed at a center frequency of 4.5 GHz for equal power dividing with all ports matched to 50 ohm. Drawing a dc current of 9.3 mA from a 1.8-V supply voltage, the fabricated circuit exhibits an insertion loss less than 0.16 dB and a return loss better than 30 dB at the center frequency while maintaining good isolation between the output ports. The active area of the miniaturized Wilkinson power divider is 150x100 um2, which is suitable for system integration in monolithic microwave integrated circuit (MMIC) applications.
For the design of a 4.4-GHz coupler, the total chip area including the pad frame is 640x720 um2, while the active area only occupies 400x200 um2. Consuming a dc power of 25.2 mW from a 1.8-V supply voltage, the fabricated circuit exhibits an insertion loss of 0.23 dB while maintaining good return loss and port isolation at the center frequency.
Subjects
主動電感
偶合器
分波器
極小化
active inductor
phase shifter
wilkinson power divider
hybrid
Type
thesis